Method for unidirectional and bidirectional label switched path setup in a label switched network

Abstract

Label contention in a label switched network is resolved by applying a contention resolution scheme that reconciles policies for handling unidirectional and bidirectional label switched path setup.

1. A method of resolving label contention in a network, comprising:
 receiving a first label switched path setup message sent by a first node in the network; 
 determining whether the first label switched path setup message contends for a same label assigned or suggested in a second label switched path setup message sent by a second node in the network; and 
 giving priority to the second label switched path setup message if the first label switched path setup message is a label request and if the second label switched path setup message is a label reply. 
 
   
   
     2. The method of  claim 1 , further comprising:
 giving priority to the second label switched path setup message if the first label switched path setup message is a setup message for a unidirectional label switched path and if the second label switched path setup message is a setup message for a bidirectional label switched path. 
 
   
   
     3. The method of  claim 2 , further comprising:
 giving priority in accordance with a first contention policy if both the first and second label switched path setup messages are setup messages for unidirectional label switched paths, and in accordance with a second contention policy, different from the first contention policy, if both the first and second label switched path setup messages are setup messages for bidirectional label switched paths. 
 
   
   
     4. The method of  claim 3 , wherein the first contention policy gives priority in accordance with a downstream label selection. 
   
   
     5. The method of  claim 4 , wherein the second contention policy gives priority to one of the nodes with a higher node identification. 
   
   
     6. The method of  claim 1 , wherein the network utilizes Generalized Multi-Protocol Label Switching (GMPLS). 
   
   
     7. A method of resolving label contention in a network, comprising:
 receiving a first label switched path setup message sent by a first node in the network; 
 determining whether the first label switched path setup message contends for a same label assigned or suggested in a second label switched path setup message sent by a second node in the network; and 
 giving priority to the second label switched path setup message if the first label switched path setup message is a setup message for a unidirectional label switched path and if the second label switched path setup message is a setup message for a bidirectional label switched path. 
 
   
   
     8. The method of  claim 7 , further comprising:
 giving priority in accordance with a first contention policy if both the first and second label switched path setup messages are setup messages for unidirectional label switched paths, and in accordance with a second contention policy, different from the first contention policy, if both the first and second label switched path setup messages are setup messages for bidirectional label switched paths. 
 
   
   
     9. The method of  claim 8 , wherein the first contention policy gives priority in accordance with a downstream label selection. 
   
   
     10. The method of  claim 9 , wherein the second contention policy gives priority to one of the nodes with a higher node identification. 
   
   
     11. The method of  claim 7 , wherein the network utilizes Generalized Multi-Protocol label Switching (GMPLS). 
   
   
     12. A method of resolving label contention in a network, comprising:
 receiving a first label switched path setup message sent by a first node in the network; 
 determining whether the first label switched path setup message contends for a same label assigned or suggested in a second label switched path setup message sent by a second node in the network; and 
 giving priority in accordance with a same contention policy where the first label switched path setup message or the second label switched path setup message is a setup message for a unidirectional label switched path or a bidirectional label switched path. 
 
   
   
     13. The method of  claim 12 , wherein the contention policy gives priority to one of the nodes with a higher node identification. 
   
   
     14. The method of  claim 12 , wherein the network utilizes Generalized Multi-Protocol label Switching (GMPLS). 
   
   
     15. A system for resolving label contention in a network, comprising:
 means for receiving a first label switched path setup message sent by a first node in the network; 
 means for determining whether the first label switched path setup message contends for a same label assigned or suggested in a second label switched path setup message sent by a second node in the network; and 
 means for giving priority to the second label switched path setup message if the first label switched path setup message is a label request and if the second label switched path setup message is a label reply. 
 
   
   
     16. The system of  claim 15 , further comprising:
 means for giving priority to the second label switched path setup message if the first label switched path setup message is a setup message for a unidirectional label switched path and if the second label switched path setup message is a setup message for a bidirectional label switched path. 
 
   
   
     17. The system of  claim 16 , further comprising:
 means for giving priority in accordance with a first contention policy if both the first and second label switched path setup messages are setup messages for unidirectional label switched paths, and in accordance with a second contention policy, different from the first contention policy, if both the first and second label switched path setup messages are setup messages for bidirectional label switched paths. 
 
   
   
     18. The system of  claim 17 , wherein the first contention policy gives priority in accordance with a downstream label selection. 
   
   
     19. The system of  claim 18 , wherein the second contention policy gives priority to one of the nodes with a higher node identification. 
   
   
     20. The system of  claim 15 , wherein the network utilizes Generalized Multi-Protocol Label Switching (GMPLS).